A facile fabrication of micro/nano-sized silicon/carbon composite with a honeycomb structure as high-stability anodes for lithium-ion batteries

摘要

Silicon based anodes for lithium ion batteries have attracted great interests because of a high theoretical capacity of 4200 mAh g(-1). To achieve high performance and low cost silicon anodes by overcoming their inherent drawbacks, a facile route was carried out to successfully encapsulate the micro/nano-sized silicon particles into a nitrogen-enriched porous carbon matrix using CaCO3 as the structural template, polyacrylonitrile (PAN) as the carbon and nitrogen source. The resultant porous composite (Si/PC) exhibits dramatically enhanced cycling stability and excellent rate performance, about 830 mAh g(-1) can be achieved after discharged/charged at 200 mA g(-1) for 200 cycles with a high retention of 81.5% based on the second reversible capacity, furthermore, 230 mAh g(-1) can still be maintained even at a high current density of up to 3200 mA g(-1). The enhanced performance is ascribed to the unique porous structure that can accommodate the volume variation of silicon during the lithiation/delithiation process, and the increased conductivity due to the enriched nitrogen species in the carbon network.